Water-cooled measuring probe for measuring the temperature of hot liquid metal baths, in particular in melting or refining furnaces

ABSTRACT

The invention relates to a water-cooled measuring probe for continuously measuring the temperature of hot liquid metal baths, comprising an inner tube and an outer tube connected with each other under formation of a probe head to which a sensing portion containing a thermocouple is joined, and a plug connection for connecting a compensating line with said sensing portion; a sleeve closed at its upper end and open at its lower end surrounding the plug connection and means for sealingly pressing said sensing portion against said lower end of said sleeve. By means of this arrangement the access of water and humidity to the plug connection is absolutely avoided.

States Patent 1 Poiierl et al.

[ 4] WATER-COOLED MEASURING PROBE roR MEASURlNG IIE TEMPERATURE or IIoTLI UID METAL BATHS, IN PARTICULAR IN MELTING 0R REFINING FURNACES [75]Inventors: Gunter Poferl; Gerald Schmidt;

ll-lellmuth Smejkal, all of Linz, Austria [73] Assignee: VerinigteOsterrlich ische Eisen-und Stahlwerke Aktiengesellschait, Linz, Austria[22] Filed: Aug. 9, 1971 [21] Appl. No.: 170,215

[30] Foreign Application Priority Data Dec. 25, 1973 Truppe et al.73/359 Truppe et all 73/359 FOREIGN PATENTS OR APPLlCATlONS 583,78l9/1959 Canada 73/359 [5 7] ABSTRACT The invention relates to awater-cooled measuring probe for continuously measuring the temperatureof hot liquid metal baths, comprising an inner tube and an outer tubeconnected with each other under formation of a probe head to which asensing portion containing a thermocouple is joined, and a plugconnection for connecting a compensating line with said sensing portion;a sleeve closed at its upper end and open at its lower end surroundingthe plug connection and means for sealingly pressing said sensingportion against said lower end of said sleeve. By means of thisarrangement the access of water and humidity to the plug connection isabsolutely avoided.

8 Claims, 3 Drawing Figures PMENIEI] DECZS um 3780.583

sum 1 0F 3 IN\-EI\'TOR$. l/NTER POFERL, GERALD SCHMIDT & HELL NUTHSNEJKAL PATEN ED 3.780.583

SHEETZUF3 INVENTORS. ONT/ER POFERL GERALD SCHMIDT & HELLNUTH SNEJ/(ALWATER-COOLED MEASURING PROBE FOR MEASURING THE TEMPERATURE OF HOT LIQUIDMETAL BATI-IS, IN PARTICULAR IN MELTING R REFINING FURNACES Theinvention relates to a water-cooled measuring probe for continuouslymeasuring the temperature of hot liquid metal baths, in particular inmelting or refining furnaces, comprising an inner tube, an outer tubeand a guiding tube between said inner and outer tubes for the formationof a cooling agent circulation, a sensing portion containing athermocouple being releasably fixed to the head of the probe and beingconnectable with a compensating line ending in the probe head by meansof a plug connection. I

In water-cooled measuring probes which are inserted into a metal bathfrom above there is the problem of preventing condensing water fromentering into the sensing portion whichis releasably connected with theprobe head. In comparatively short measuring probes with a length ofsome meters this problem may be solved by connecting a tube receivingthe compensating line with the inner tube of the measuring probe at acertain distance above the plug connection, e.g., by means of a tensionnut.

In measuring probes of great length (about 20 m) as they are used forbig converters, this construction cannot be employed because owing tothe fact that the water-cooled inner tube of the measuring probe and thenot cooled tube receiving the compensation line are heated to adifferent degree, a play occurs; thus, condensing water which is alwayspresent in the inner tube may enter into the area of the plug connectionwhere it may cause a short circuit. When the connection between the tubereceiving the compensating line and the inner tube becomes leaky, theprobe has to be removed. Such a defect cannot'be remedied at the siteduring an operation pause, but the measuring probe has to be broughtinto the workshop where it has to be repaired.

The invention is aimed at avoiding these disadvantages and difficultiesand in a probe of the kind defined in the introduction resides in thatthe plug connection and, if desired, part of the compensating line aresurrounded by a sleeve which is closed at its upper end and open at itslower end, against whose lower end the sensing portion may sealingly bepressed and which if desired, is also sealed against the inner tube ofthe probe head.

Advantageously the sleeve is screwed into the inner tube of the probehead. This has the particular advantage that the sealing against thecondensing water may be controlled at the site because the sleeve shapedconstruction element may be inserted into the inner space of the probefrom below.

Suitably the sleeve is closed at its upper end by a stopper made ofrubber, elastic plastics, cast resin or the like, comprsing a bore forguiding through the compensating line.

The sleeve may comprise two parts connected with each other, namely anupper part including an axial canal for receiving a guiding rodconnected with the plug and an eccentrical bore arranged separately fromsaid axial canal for receiving the compensating line, and a lower partwith a hollow space above the plugfor receiving a plurality of coils ofthe compensating line.

The axial canal has a square cross section and the guiding rod having aflange adapted to this cross section is displaceable in longitudinaldirection in the canal.

The sleeve may also comprise a single structural element, in whose upperend, which is closed by the stopper, the plug or the socket of the plugconnection is embedded.

In order that the invention may be more fully understood, twoembodiments thereof shall now be explained with reference to theaccompanying drawings.

FIG. 1 shows in a partly vertical sectional view an embodiment with asleeve comprising two parts, and

FIG. 2 shows in a similar representation an embodiment comprising asleeve in one part,

FIG. 3 is a view of the embodiment of the invention taken along linesA--A in FIG. 1.

In FIG. 1 numeral 1 denotes the water-cooled probe with the probe head2. It comprises the inner tube 3, the outer tube 4 and the guiding tube5 arranged between the inner and the outer tubes for the formation of acoolant circulation. The probe head comprises the inner tube 3', whichhas the same diameter as the inner tube 3 of the probe, the outer tube4' and the guiding tube 5'; the latter two spring in as compared to thetubes 4 and 5 like shoulders so that the probe head 2 has a smallerdiameter than the probe itself. The sensing portion 6 containing thethermocouple (not illustrated) is releasably joined to the lower end ofthe probe head; in the embodiment according to FIG. 1 it is joined bymeans of a nut 7 which is screwed into the inner tube 3 of the probehead. The set back probe head 2 and the sensing portion 6 are surroundedby a refractory jacket 8. As may be seen, also in the probe head acirculation for a coolant is present which is branched off from thecirculation of a cooling agent in the measuring probe. The sensingportion which is screwed into the probe head is provided at its upperend with a rapid connection for joining the thermocouple limbs to thecompensating line 9; this rapid connection comprises a socket l0 and aplug 11. Above the plug connection the compensating line is laid into aplurality of coils 12, so that it is possible to remove the plugconnection by pulling out the coils.

According to the invention the plug connection and part of thecompensating line are surrounded by a sleeve 13 which in the embodimentaccording to FIG. 1 comprises two parts. It comprises the upper part 14and the lower part 15. The upper end of the sleeve is closed by astopper 16 which is made of rubber, elastic plastics or cast resin andwhich is provided with an eccentrical bore 17 through which thecompensating line 9 extends. The lower end of the sleeve, which is open,is sealed by a sealing ring 18 against the flange 19 of the sensingportion 6; when the nut 7 is tightened, the sealing is pressed together.The sealing may be made of rubber, lead, copper or similar material. Thelower part of the sleeve is connected by a screw connection 20 with theinner tube 3' of the probe head and sealed against it by means of theannular sealing 21.

When the sleeve comprises two parts as illustrated in FIG. 1, the upperpart is advantageously provided with an axial canal 22, in which aguiding rod 23, which is connected with the plug connection 10, 11, isdisplaceable in longitudinal direction. This canal advantageously has asquare cross section in order to prevent any torsional movements asshown in FIG. 3; the flange 24 at the upper end of the guiding rod isadapted to this cross section. The upper sleeve part 14 is connectedwith the lower sleeve part by a screw connection or adhesive connection25 which is gas and water tight. A floor 26 is screwed into the lowerend of the sleeve part 14 which floor comprises an opening through whichthe guiding rod 23 extends. In this manner a sufficiently great hollowspace is formed between the plug connection and the upper sleeve partfor receiving a greater number of coils of the compensating line. Theconnection of the guiding rod with the plug connection is suitablyachieved by means of a guiding body 27 of electrically insulatingmaterial.

By means of the described construction the access of water and humidityto the plug connection is absolutely avoided. It is possible thatcondensing water from above penetrates in the direction of the arrows 28into the gap between the sleeve part 14 and the inner tube of the probe,but it is impossible that this water further penetrates through thesealings 16, 21 and 18. The water steam which is freed from therefractory jacket 8 and ascends in the direction of the arrows 29likewise cannot penetrate these sealings. After the refractory jacketwhich is connected with the probe head by means of a bayonet catch isreleased, during removal and insertion of the sensing portion 6, theplug connection 10, 11 may be pulled out of the probe head 2 so faruntil it may be released without difficulties. By designing the guidingrod 23 and its guiding flange 24, re-

spectively, to be square, an unintentional co-rotation of the sensingportion is avoided when the nut 7 is screwed in so that the compensatingline cannot be torn. The lower part 15 of the sleeve which is connectedwith the inner tube 3' is cooled together with the inner tube 3' so thatthe space 31 surrounding the plug connection is correspondingly cooledas well.

For obtaining results of sufficient accuracy the temperature must notincrease above 100 C in this space. Temperature changes which may occurin the upper part of the probe may effect an alteration in the length ofthe sleeve 13, but this has no influence on the function of the seals16, 21 and 18. In particular the pressure of the flange 19 onto thesealing 18 remains constant and prevents any penetration of humidity.

In FIG. 2 the same construction elements are denoted with the samenumerals as in FIG. 1. In this embodiment a sleeve 32 is employed whichcomprises a single part; at the upper end of this sleeve which is closedby means of a stopper 16' made of rubber or cast resin, the plug 11 isembedded which is connected with the compensating line 9'. Thus thespace 31 surrounding the socket l0 and the plug 11 has a very smallvolume. When the sensing portion 6 is removal and insertion the plug 11remains in the sleeve 32. When removing the sensing portion 6, after thescrew connection 20 has been released, in order to be able to pull thesleeve out of the probe head 2 in downward direction to a sufficientextent it is necessary to arrange the compensating line 9' in a numberof coils; not shown in the drawing, in the upper part of the probe. Alsoin this embodiment neither condensing water running off in downwarddirection as shown by the arrows 28, nor humid gas ascending upwardly asillustrated by the arrows 29 may penetrate into the plug connection.

What is claimed is:

1. A water-cooled measuring probe for continuously measuring thetemperature of hot liquid metal baths by substantially verticalimmersion, comprising an inner tube having an upper portion and a lowerportion, an

outer tube surrounding the inner tube and having an upper portion and alower portion, a guiding tube between the inner and outer tubesproviding a means for circulation of cooling water and having an upperportion and a lower portion, a probe head defined by the inner tube,outer tube and guiding tube lower portions with the outer tube connectedto the inner tube at the probe bottom, a sensing portion releasablyjoined to the probe head and containing a thermocouple, a compensatingline ending in the probe head, a plug connection for connecting thecompensating line with the sensing portion, a sleeve within the innertube with the plug connection within the sleeve, the sleeve closed atits upper end and open at its lower end, and means for sealinglypressing the sensing portion against the lower end of the sleeve toenclose the plug connection within the sleeve.

2. The measuring probe set forth in claim 1, wherein the sleeve alsoencloses part of the compensating line.

3. The measuring probe set forth in claim 1, wherein the sleeve issealed against the inner tube of the probe head.

4. The measuring probe set forth in claim 1, wherein the sleeve isscrewed into the inner tube lower portion of the probe head.

5. A water-cooled measuring probe for continuously measuring thetemperature of hot liquid metal baths by substantially verticalimmersion, comprising an inner tube having an upper portion and a lowerportion, an outer tube surrounding the inner tube and having an upperportion and a lower portion, a guiding tube between the inner and outertube providing a means for circulation of cooling water and having anupper portion and a lower portion, a probe head defined by the innertube, outer tube and guiding tube lower portions with the outer tubeconnected to the inner tube at the probe bottom, a sensing portionreleasably joined to the probe head and containing a thermocouple, acompensating line ending in the probe head, a plug connection forconnecting the compensating line with the sensing portion, a guidingrod, a sleeve within the inner tube with the plug connection within thesleeve, the sleeve having an upper part connected to a lower part andclosed at its upper end and open at its lower end, the upper partincluding an axial canal for receiving said guiding rod connected withthe plug and an eccentrically arranged bore separate from the axialcanal for receiving the compensating line, the lower part providing ahollow space above the plug for receiving a plurality of coils of thecompensating line, and means for sealingly pressing the sensing portionagainst the lower end of the sleeve to enclose the plug connectionwithin the sleeve.

6. The measuring probe set forth in claim 5, wherein the axial canal hasa square cross-section and the guiding rod includes a flange adapted tothe cross-section to limit rotation of the guiding rod, the flange beinglongitudinally displacable in the canal.

7. A water cooled measuring probe for continuously measuring thetemperature of hot liquid metal baths by substantially verticalimmersion, comprising an inner tube having an upper portion and a lowerportion, an outer tube surrounding the inner tube and having an upperportion and a lower portion, a guiding tube between the inner tube andouter tube providing a means for circulation of cooling water and havingan upper portion and a lower portion, a probe head defined by the innertube, outer tube and guiding tube lower portions with the outer tubeconnected to the inner tube at the probe bottom, a sensing portionreleasably joined to the probe head and containing a thermocouple, acompensating line ending in the probe head, a plug connection forconnecting the compensating line with the sensing portion, a sleevewithin the inner tube with the plug connection within the sleeve, thesleeve closed at its upper end and open at its lower end, a stopperadapted to be inserted in the upper end of the sleeve to form a tightfit and made of a material selected from the group consisting of rubber,elastic plastic, and cast resin, the stopper having a bore for thecompensating line to pass through, and means for sealingly pressing thesensing portion against the lower end of the sleeve to enclose the plugconnection within the sleeve.

8. A water cooled measuring probe for continuously measuring thetemperature of hot liquid metal baths by substantially verticalimmersion, comprising an inner tube having an upper portion and a lowerportion, an

outer tube surrounding the inner tube and having an upper and a lowerportion, a guiding tube between the inner and outer tubes providing ameans for circulation of cooling water and having an upper portion and alower portion, a probe head defined by the inner tube, outer tube andguiding tube lower portions with the outer tube connected to the innertube at the probe bottom, a sensing portion releasably joined to theprobe head and containing a thermocouple, a compensating line ending inthe probe head, a plug connection for connecting the compensating linewith the sensing portion, a sleeve within the inner tube formed of asingle constuctional element with the plug connection within the sleeve,the sleeve having its upper end closed by a stopper embedding a part ofthe plug connection and having its lower end open, and means forsealingly pressing the sensing portion against the lower end of thesleeve to enclose the plug connection within the sleeve.

$19,7 3? Q UNITED STAS PATENT QFFICE CERTIFICATE 6F -COECTK Patent No.3,780,583 A Dated Dec 5: 973

Inventor(s) Poferl et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

First wage, Item [73], "Verinigte Osterrlichische Eisen-und" w should be--Vereinigte Usterreichische Eisenund--;

Col. 1, line 57, "comprsing" should read. --comprising--; and

Col; 3, lines 51 and 52, "removal and insertion" should read --removedor inserted";

Signed and sealed this 21st day of May 1974.

LSEAL) Attest:

EDWARD M.FLETCHER,JR. A C. MARSHALL DANN Attesting Officer Commissionerof Patents 22 3 I UNITED STATES PATENT QFFICE CERTIFICATE OF CORRECTIONPatent 3,7 ,5 3 Dated Dec. 25, 1973 Inventor(s) Poferl et a1.

It is certifiedrhat error appears in the above-identified patent andthat said Letters Patent are-hereby corrected as shown below:

" First nage, Item [73], "Verinigte Osterrlichische Eisen-und" .1

should be --Vereinigte Usterreichische Eisenund--;

Col. 1, line 57, "comprsing" should read-.,--comprising--; and Col. 3,lines 51 and 52, "removal and insertion" should read --removed orinserted;

Signed and sealed 'this' 21st day of May 1974".

( SEAL) \ttest:

EDWARD M.FLETCHER,JR. C, MARSHALL DANN \ttesting Officer 1 Commissionerof Patents

1. A water-cooled measuring probe for continuously measuring thetemperature of hot liquid metal baths by substantially verticalimmersion, comprising an inner tube having an upper portion and a lowerportion, an outer tube surrounding the inner tube and having an upperportion and a lower portion, a guiding tube between the inner and outertubes providing a means for circulation of cooling water and having anupper portion and a lower portion, a probe head defined by the innertube, outer tube and guiding tube lower Portions with the outer tubeconnected to the inner tube at the probe bottom, a sensing portionreleasably joined to the probe head and containing a thermocouple, acompensating line ending in the probe head, a plug connection forconnecting the compensating line with the sensing portion, a sleevewithin the inner tube with the plug connection within the sleeve, thesleeve closed at its upper end and open at its lower end, and means forsealingly pressing the sensing portion against the lower end of thesleeve to enclose the plug connection within the sleeve.
 2. Themeasuring probe set forth in claim 1, wherein the sleeve also enclosespart of the compensating line.
 3. The measuring probe set forth in claim1, wherein the sleeve is sealed against the inner tube of the probehead.
 4. The measuring probe set forth in claim 1, wherein the sleeve isscrewed into the inner tube lower portion of the probe head.
 5. Awater-cooled measuring probe for continuously measuring the temperatureof hot liquid metal baths by substantially vertical immersion,comprising an inner tube having an upper portion and a lower portion, anouter tube surrounding the inner tube and having an upper portion and alower portion, a guiding tube between the inner and outer tube providinga means for circulation of cooling water and having an upper portion anda lower portion, a probe head defined by the inner tube, outer tube andguiding tube lower portions with the outer tube connected to the innertube at the probe bottom, a sensing portion releasably joined to theprobe head and containing a thermocouple, a compensating line ending inthe probe head, a plug connection for connecting the compensating linewith the sensing portion, a guiding rod, a sleeve within the inner tubewith the plug connection within the sleeve, the sleeve having an upperpart connected to a lower part and closed at its upper end and open atits lower end, the upper part including an axial canal for receivingsaid guiding rod connected with the plug and an eccentrically arrangedbore separate from the axial canal for receiving the compensating line,the lower part providing a hollow space above the plug for receiving aplurality of coils of the compensating line, and means for sealinglypressing the sensing portion against the lower end of the sleeve toenclose the plug connection within the sleeve.
 6. The measuring probeset forth in claim 5, wherein the axial canal has a square cross-sectionand the guiding rod includes a flange adapted to the cross-section tolimit rotation of the guiding rod, the flange being longitudinallydisplacable in the canal.
 7. A water cooled measuring probe forcontinuously measuring the temperature of hot liquid metal baths bysubstantially vertical immersion, comprising an inner tube having anupper portion and a lower portion, an outer tube surrounding the innertube and having an upper portion and a lower portion, a guiding tubebetween the inner tube and outer tube providing a means for circulationof cooling water and having an upper portion and a lower portion, aprobe head defined by the inner tube, outer tube and guiding tube lowerportions with the outer tube connected to the inner tube at the probebottom, a sensing portion releasably joined to the probe head andcontaining a thermocouple, a compensating line ending in the probe head,a plug connection for connecting the compensating line with the sensingportion, a sleeve within the inner tube with the plug connection withinthe sleeve, the sleeve closed at its upper end and open at its lowerend, a stopper adapted to be inserted in the upper end of the sleeve toform a tight fit and made of a material selected from the groupconsisting of rubber, elastic plastic, and cast resin, the stopperhaving a bore for the compensating line to pass through, and means forsealingly pressing the sensing portion against the lower end of thesleeve to enclose the plug connection within the sleeve.
 8. A watercooled measuring Probe for continuously measuring the temperature of hotliquid metal baths by substantially vertical immersion, comprising aninner tube having an upper portion and a lower portion, an outer tubesurrounding the inner tube and having an upper and a lower portion, aguiding tube between the inner and outer tubes providing a means forcirculation of cooling water and having an upper portion and a lowerportion, a probe head defined by the inner tube, outer tube and guidingtube lower portions with the outer tube connected to the inner tube atthe probe bottom, a sensing portion releasably joined to the probe headand containing a thermocouple, a compensating line ending in the probehead, a plug connection for connecting the compensating line with thesensing portion, a sleeve within the inner tube formed of a singleconstuctional element with the plug connection within the sleeve, thesleeve having its upper end closed by a stopper embedding a part of theplug connection and having its lower end open, and means for sealinglypressing the sensing portion against the lower end of the sleeve toenclose the plug connection within the sleeve.